Rationalizing venepuncture pain: comparison of lignocaine injection, Butterfly (21 gauge and 23 gauge) and Venflon (20 gauge).

Two hundred and seventy-eight patients scheduled for all types of surgery and premedicated with diazepam and metoclopramide were randomly allocated to one of four groups to compare the relative pain of an injection of 0.25 ml of lignocaine 1% via a 25 gauge needle with the pain of the siting of a 21 gauge Butterfly (Abbott), 23 gauge Butterfly or a 20 gauge Venflon (Vigo Spectramed). The injection of lignocaine and insertion of the 23 gauge Butterfly were associated with the least complaints of pain and least observed responses to pain. The 21 gauge Butterfly and 20 gauge Venflon were associated with complaints of greater pain and more pain responses. We conclude that a pre-cannulation injection of lignocaine causes minimal discomfort and is the most appropriate means of reducing the discomfort of venous cannulation when not using skin penetrating analgesic creams.